Climber-type scaffold



Dec. 13, 1966 Flled May 19, 1965 United States Patent O 3,291,257 CLIMBER-TYPE SCAFFOLD Forest M. Ellis, 2301 N. 59th St., Kansas City, Kans. Filed May 19, 1965, Ser. No. 456,918 7 Claims. (Cl. 182--134) This invention relates to new and useful improvements in scaffolding, and has as its principal object the provision of a scaffolding device consisting of a platform movable vertically along a vertical standard, and having a mechanism whereby a man standing on said platform may move said platform up or down the standard at will. The device is intended as a light-weight, one-man scaffold having approximately the same height as a step ladder or the like, but is not limited to such usage, as will be readily apparent.

Generally, this object is accomplished by means of a pair of gripper devices mounted one above the other on the standard and each forming a toe stall in which the user respectively engages his feet, the platform being carried by one of the grippers, each gripper being so constructed that it will slide freely upwardly on the standard,

but having locking means preventing downward movement thereof along the standard, whereby the user may climb the standard with a simple stepping motion, supporting his weight on one gripper while elevating the other, the locking means being releasable by a simple motion of the users foot to permit a reversal of the action for descending movement.

Other objects are simplicity and economy of construction, efficiency and dependability of operation, safety of use, and adaptability for use in many applications.

With these objects in view, as well as other objects which will appear in the course of the specification, reference will be had to the accompanying drawing, wherein:

FIG. l is a side elevational view of a climber-type scaffold embodying the present invention, with portions broken away,

FIG. 2 is a top plan View of the device as shown in FIG. l,

FIG. 3 is an enlarged, fragmentary sectional view taken on line III-III of FIG. 2, with parts left in elevation,

FIG. 4 is a fragmentary sectional view taken on line IV-IV of FIG. 3, and

FIG. 5 is a sectional view taken on line V--V of FIG. 3.

Like reference numerals apply to similar parts throughout the several views, and the numeral 2 applies to a vertical standard comprising preferably a cylindrical rod or heavy-walled tubing. Said standard may be of any desired height, and the lower end thereof is engaged in a socket member 4 aixed centrally to a planar base 6 adapted to be supported on a ground or floor surface 8 adjacent a vertical wall 10 in connection with which it is desired to use the scaffold.

Mounted on standard 2, so as to be movable vertically therealong, are an upper gripper device indicated generally by the numeral 12, and a lower gripper device indicated generally by the numeral 14, said grippers being vertically spaced apart on said standard. Said grippers are largely identical with each other, as best shown in FIGS. 3 and 4, each including an internal wedge carrier tube 16 having a sliding lit on standard 2. Adjacent the lower end of said tube, four angularly spaced apart rectangular windows 18 are formed therein. Supported in each of of said windows is a wedge 20, the inner surface thereof being cylindrically curved to engage and conform to the surface of standard 2, and having a facing 22 of a material providing a good frictional grip against said standard, an epoxy braking lining material having been found quite satisfactory. The outer surface of each wedge 20 is planar and is inclined inwardly and upwardly toward the axis of the standard.

3,291,257 Patented Dec. 13, 1966 lCC Surrounding carrier tube 16, and vertically slidable thereon, is a tubular housing 24, the lower portion of said housing being taperingly enlarged and having four longitudinal grooves 26 formed internally therein for receiving respectively therein the portions of wedges 20 which extend radially outwardly from tube 16, said grooves being tapered in depth to conform to the inclination of the outer surfaces of said wedge. The lower-most skirt portion 28 of housing 24 is of larger diameter than carrier tube 16, and is spaced outwardly therefrom. Said skirt nevertheless is maintained in accurately centered relation to the carrier tube by a ring 30 welded or otherwise fixed externally to tube 16 at the lower end thereof, said ring having a peripheral flange 32 which slidably engages the internal surface of skirt 28.

Carrier tube 16 extends above the upper end of housing 24, and the extended portion thereof is externally threaded. A heavy ring 34 encircles the threaded portion of tube 16, and is secured thereon by a pair of lock nuts 36 and 38 threaded on on said tube respectively above and below said ring. Ring 34 of upper gripper device 12 has an outwardly extending arm 40 formed integrally therewith, and ring 34 of lower gripper device 14 has a pair of outwardly extending arms 42 and 44 formed integrally therewith, for purposes which will presently appear. The lower lock nut 38 of each gripper member also limits the upward movement of the associated housing 24 with respect to carrier tube 16, as will be described.

Integral with or alixed to housing 16 of lower gripper device are a pair of horizontal, forwardly divergent arms 46. Said arms support a generally triangular horizontal work platform 48 welded or otherwise affixed thereto. At the spaced apart forward ends of arms 46 are rotatably mounted a pair of wheels 50 adapted to rest in rolling contact with wall 10. Aixed to platform 48 in spaced apart relation from standard 2 is a toe stall including a step block 52 affixed to the platform by screws 51. A strap member 54 has its ends affixed to said step block by screws 56, and passed over the top of said block to form a toe hole 53 therebetween. The user may insert the toe of his shoe through said toe hole, and thereafter either rest his weight on block 52, or by exerting upward pressure against strap 54, cause gripper member 14 to be elevated on standard 2 as will be described. Arm 42 affixed to carrier tube 16 of gripper member 14 extends alongside step block 52 as shown, prefrably at a slightly lower level than the top surface of said block, whereby the user can, by tilting his foot, exert a downward pressure on arm 42 and a simultaneous upward pressure on strap 54. This elevates housing 24 with respect to tube 16 of the gripper to release the wedges as will be described.

Housing 24 of upper gripper member 12 is provided at its lower end with an integral, horizontally projecting shelf 60 to which is affixed a toe stall including a block 62 affixed by screws 64, and to which block a strap member 66 is attached by screws 68 to form a toe hole 70 therebetween in precisely the same manner las step block 52 and strap 54, except that the two step blocks are horizontally offset from each other. Arm 40 affixed to tube 16 of the upper gripper extends adjacent and slightly below the level of step block `62, having the same relation thereto as arm 42 has to step block 52.

Housing 24 of upper gripper member 12 al-so has a horizontally extending integral arm 72 which is angularly aligned with arm 44 Iof the lower gripper member. Arms 72 and 44 are interconnected by a vertical bolt 74, said ibo-lt being affixed in arm 72 by a lock nut 76, extending slidably through a hole 78 provided therefor in arm 44, and having nuts 80 threaded on the lower end thereof. Bolt 74 limits the vertical separation between the grippers 3 12 and 14, and is also -a safety device, as will be described.

In use, with standard 2 seated in socket 4 of base 6, and with platform 4S close to the ground with wheels 50 engaging wall 10, the user inserts the toes of his shoes respectively in the toe holes 58 and 70, supporting his weight on step blocks 52 and 62. It will be seen that his weight tends to force housings 24 of the grippers downwardly, causing them to press wedges firmly inwardly against standard 2. The greater the operators weight, the greater will be the pressure of the wedges, and no slippage can occur. Then, assuming the parts have the positions shown in FIG. 3, the operator shifts all of his weight to upper step block 62, and lifts upwardly against strap 54 with his other foot. This elevates housing 24 of the lower gripper relative to the associated carrier tube 16, relieving the pressure on the wedges and allowing the lower gripper to slide upwardly along the standard, tube `1.6 'being elevated by engagement of the housing with lower lock nut 38. When the lower gripper is elevated to the extent desired, `or until the upper end thereof engages the lower end of upper gripper 12, this movement being permitted -by safety bolt 74, the operator again applies his weight to step block 52, causing lower housing 24 to be lowered with respect to tube 16 to reapply pressure to wedges 20 of the lower gripper and preventing downward movement of said gripper on the standard. In this connection, it will be understood that lower lock nut 38 is spaced above the upper end olf housing 24 only to suchan extent that even when said housing is fully elevated against said lock nut, wedges 20 still have a light frictional engagement with the standard, the friction thereby provided not being great enough to prevent sliding of the gripper on the standard, but preferably being of suicient magnitude to support the weight of tube 16 only. This friction supplies the initial resistance to downward movement of tube 16 which facilitates relative downward movement of the housing to apply force to the wedges. This fine adjustment is not mandatory, it being possible to provide the necessary relative movement of the tube and housing by moving the entire gripper upwardly at a rapid rate, then moving housing 24 downwardly more rapidly than gravity can overcome the upward inertia of tube 16. However, the adjustment does increase the ease and convenience of usage, and is not diicult to obtain, particularly if the material of the wedge facings 22 is of a slightly yieldable consistency.

The operator then shifts his entire weight to step block 52, and by lifting upwardly against strap 66, elevates upper gripper 12 in precisely the same manner as that described above in connection with lower gripper 14. In this case, the extent to which Igripper 12 may be elevated is limited by safety bolt 74, this limitation being irnportant to safety and comfort of usage in that the operatorss feet should never be permitted to become so far vertically spaced apart that he cannot readily shift his weight from one foot to the other. A step limitation of Iabout six inches has been found entirely satisfactory. By repeating the cycle just described, the operator may elevate himself, and of course platform 48, to any desired elevation on standard 2 by a step-by-step climbing action, wheels 50 rolling Iupwardly along wall 10. He can then Withdraw -his toes from toe holes 58 and 70 and stand on platform 48 to perform whatever tasks may be required.

When the operator desires to descend the standard, the action is only slightly more complicated. Assuming again that the parts have the positions shown in IFIG. 3, the operator supports all of his weight on the foot engaging step 'block S2, then tilts the foot engaged in the toe hole 70 slightly forwardly so that the toe thereof engages arm 40 aixed to carrier tube 16 of the upper gripper. By tilting his foot with some force, he exerts a downward pressure on arm 40 and a simultaneous upwand pressure on strap 66. This elevates housing 24 relative to tube 16 of the upper gripper, releasing the wedges thereof and allo-wing the upper gripper to be moved slidably down the standard, so longas the operator maintains his foot in the position descri-bed. W-hen gripper 12 has been lowered to the upper end of gripper 14, the operator elevates his toe out of engagement with arm 40, thereby allowing the wedges -of the upper gripper to reset. He then shifts his weight to block 62, and tilts the toe of the other foot to engage arm 42, thereby releasing the wedges of the lower gripper, and so on. The foot action required by the operator, while apparently requiring a -somewhat lengthy and wordy description,is actually quite natural and easy, and is readily understood and performed by the operator. T-he downward movement of lower gripper 14 is of course 'limited by safety bolt 74, and is doubly important in the descending action, since the operator must tbe free at all times not only to shift his weight from one foot to the other, but also to tilt his feet as just described. Safety bo-lt 74 also has the function of catching and supporting lower gripper 14 in the unlikely occurrence that the wedges 20 of the lower gripper should fail to grip the standard properly or should sli-de thereon for any reason when weight is supported -by platform 48. I-f the upper gripper should fail for any reason, it will lbe caught and arrested by the lower gripper. The chance that both .grippers could fail simultaneously is indeed extremely remote, and the device is therefore quite safe.

It will be seen that platform 48, as well as both step blocks 52 and 62, are disposed between standard 2 and wall 10. Therefore, any bending flexure of standard 2 which may be caused by the load will simply urge wheels 50 more tightly against wall 10, and the standard can never flex away from the wall. Base 2 also imparts stability to the standard, and may be of any size desired for the best support. If the standard were rigidly mounted at its lower end, as by driving it into the ground, then wheels 50 or any other contact between the platform and the wall, could be dispensed with. However, the extent, size and complications of the equipment required for providing a truly rigid mounting of the standard are such as to be incompatible with the desired low cost and portability, and the structure shown is therefore deemed preferable.

While I have shown and described a specific embodiment of my invention, it will be readily apparent that many minor changes of structure and operation could be made without departing from the spirit of the invention as dened by the scope of the appended claims.

What I claim as new and desire to protect by Letters Patent is:

1. A climber-type scaffold comprising:

(a) a vertical standard,

(b) a pair of gripper devices mounted slidably on said standard one above the other, each of said gripper devices including a toe stall for receiving a foot of the operator whereby he may lift one gripper device while supporting his weight on the other, each of said toe stalls including a weight-supporting step block and a strap affixed at its ends to said block and extending thereover to form a toe yhole therebetween through which the operator may insert his foot, said step block and strap being sufficiently narrow, in a direction axial to said toe hole, that the operator may rock his foot vertically in said toe hole to lower a portion of his foot below the surface of said step block,

(c) locking means included in each of said gripper devices and normally operable to permit elevation of said gripper device on said standard but to prevent lowering of said gripper device on said standard,

(d) manually operable means for releasing said locking means whereby to permit lowering of said gripper device on said standard, said releasing means including an arm extending adjacent said step block slightly below the surface thereof, and being oper- -able by downward movement thereof relative to said step block to release said locking means, and

(e) a work platform carried by one of said gripper devices.

2. A climber-type scaffold comprising:

(a) a vertical standard,

(b) a pair of gripper devices mounted slidably on said standard one above the other, each of said gripper devices including a toe stall for receiving a foot of the operator whereby he may lift one gripper device while supporting his weight on the other, each of said gripper devices comprising:

(l) a wedge carrier tube mounted coaxially for sliding movement on said standard, and having one or more windows formed therein,

(2) a wedge carried in each of said windows, said wedge having an inner surface engaging and conforming to the surface f said standard, the outer surface of said wedge being disposed outwardly from said carrier tube and being upwardly and inwardly inclined, and

(3) a tubular housing mounted coaxially for sliding movement on said carrier tube and having a longitudinal interior groove for receiving each of said wedges, said groove being tapered in depth to correspond to the inclination of the outer surface of said wedge, the toe stall of each gripper device being carried by the said housing thereof, whereby said wedges are caused to grip said standard by downward movement of said housing relative to said carrier tube, and to release their grip by upward movement of said housing relative to said carrier tube,

(c) manually operable means for elevating said gripper housing relative to its associated carrier tube whereby the wedges of the gripper are caused to release their grip on said standard, and

(d) a work platform carried by one of said gripper devices.

3. The structure as recited in claim 2 with the addition (a) adjustable means limiting the upward movement of said housing relative to said carrier tube, whereby even when it is fully elevated said wedges still have at least a light frictional contact with said standard.

4. The structure as recited in claim 3 wherein each of said wedges is provided with a facing engaging said standard, said facing being formed of a material having a degree of resilient compressibility.

5. The structure as recited in claim 2 wherein said toe stall includes a step block which supports the weight of the operator, `and wherein said releasing means includes an arm affixed to said carrier tube and extending adjacent said s-tep block and engageable by a portion of the operators foot extending from said toe stall, whereby by rocking his foot vertically the operator may exert a downward force on said arm and a simultaneous upward force on said toe stall.

6. The structure as recited in claim 2 with the addition of:

(a) a safety member extending vertically between and interconnecting the housing of the upper gripper device with the wedge carrier tube of the lower gripper device, and operable to limit the vertical separation therebetween, and when fully extended to support the weight of the lower gripper device from the upper gripper device.

7. The structure as recited in claim 6 wherein said safety member comprises a vertical rod parallel to said standard, fixed at its upper end to the housing of the upper gripper device, and having vertical sliding engagement with the carrier tube of said lower gripper device, and means on said rod for adjustably limiting the sliding movement of said lower gripper device relative theret0.

References Cited by the Examiner UNITED STATES PATENTS FOREIGN PATENTS 8/1918 Germany.

REINALDO P. MACHADO, Primary Examiner. 

1. A CLIMBER-TYPE SCAFFOLD COMPRISING:; (A) A VERTICAL STANDARD, (B) A PAIR OF GRIPPER DEVICES MOUNTED SLIDABLY ON SAID STANDARD ONE ABOVE THE OTHER, EACH OF SAID GRIPPER DEVICES INCLUDING A TOE STALL FOR RECEIVING A FOOT OF THE OPERATOR WHEREBY HE MAY LIFT ONE GRIPPER DEVICE WHILE SUPPORTING HIS WEIGHT ON THE OTHER, EACH OF SAID TOE STALLS INCLUDING A WEIGHT-SUPPORTING STEP BLOCK AND A STRAP AFFIXED AT ITS ENDS TO SAID BLOCK AND EXTENDING THEREOVER TO FORM A TOE HOLE THEREBETWEEN THROUGH WHICH THE OPERATOR MAY INSERT HIS FOOT, SAID STEP BLOCK AND STRAP BEING SUFFICIENTLY NARROW, IN A DIRECTION AXIAL TO SAID TOE HOLE, THAT THE OPERATOR MAY ROCK HIS FOOT VERTICALLY IN SAID TOE HOLE TO LOWER A PORTION OF HIS FOOT BELOW THE SURFACE OF SAID STEP BLOCK, 